[vsnet-grb-info 10571] GRB 110503A: Swift/UVOT Observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  12000
SUBJECT: GRB 110503A: Swift/UVOT Observations
DATE:    11/05/04 10:58:36 GMT
FROM:    Samantha Oates at MSSL  <sro at mssl.ucl.ac.uk>

S. R. Oates (MSSL-UCL) & M. Stamatikos (OSU/NASA/GSFC) report on behalf of the Swift-UVOT team

The Swift/UVOT began settled observations of the field of GRB 110503A 212s 
after the trigger (Stamatikos et al., GCN Circ. 11991). We detect a fading 
source in all filters at a refined position of RA(J2000), DEC(J2000)= 
132.77588 deg,52.20767 deg. This is equivalent to:

     RA (J2000)   8:51:06.21
    Dec (J2000)  52:12:27.6

with an estimated uncertainty of 0.5 arcsec (radius, 90% confidence).
This is consistent with the UVOT position reported in Stamatikos et al. 
(GCN Circ. 11991) and with the enhanced position of the X-ray afterglow 
(Goad et al., GCN Circ. 11992).
 
Preliminary magnitudes using the UVOT photometric system (Poole et al. 2008, 
MNRAS, 383, 627) for the finding chart (FC) and summed exposures at the 
location of the optical afterglow are:

Filter  T_start(s)  T_stop(s)   Exp(s)       Mag
#####################################################
wh (FC)    212        362        147     15.82 +/- 0.02
wh         864        1014       147     17.09 +/- 0.03
v          368        388        20      16.23 +/- 0.14
b          469        488        19      16.79 +/- 0.10      
u          445        464        19      15.87 +/- 0.09
uvw1       419        438        19      16.15 +/- 0.15
uvm2       394        414        19      17.27 +/- 0.32
uvw2       519        539        19      17.72 +/- 0.31
#####################################################

The values quoted above are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.02 in the direction of the burst
(Schlegel et al. 1998).